The invention relates to the field of treatment of body cavities with stents, for instance urological stents, and more particularly to such stents which are used in the treatment of prostatic hyperplasia.
More specifically, in order to fullfill the needs of beneficial treatment, the present invention relates to a device for inserting and/or locating a stent in a body cavity, especially the prostatic stent in a human male urethra to treat the prostatic hyperplasia therein. It also is possible to utilize the device of the present invention for the placing of stents in other body cavities, such as the esophagus, the biliary passage, the intestine, or the trachea.
Prostatic stents are used to keep the prostatic lobes apart, preventing the compression of the urethra and allowing free urinary flow after different types of prostatic thermal therapy methods (e.g., VLAP, TUMT, TULIP, ILC, TUNA, HIFY, cryosurgery etc.) have been utilized to treat benign prostatic hyperplasia. Such stents may also be used in provisional treatment of patients with urinary retention who are waiting for prostatic surgery or to test the effect of surgical treatment in the case of lower urinary tract obstruction induced by benign prostatic hyperplasia. As the oedema subsides, the stent can be withdrawn. If the stent material is bioabsorbable, the prostatic stent gradually loses its strength after a determinate time period, and the small fragments of the stent exit the body through urea.
Devices for placing stents in, e.g., male urethra, are known in the prior art, for instance, from U.S. Pat. No. 5,098,374 to Othel-Jacobsen (xe2x80x9cthe ""374 patentxe2x80x9d) and U.S. Pat. No. 5,160,341 to Brenneman, the entire disclosures of which are incorporated herein by way of this reference. A considerable disadvantage in the prior art devices is that the correct location of the inserting device and thus the location of the stent to be placed inside the body cavity is not known. Thus, when using such prior art devices, a visualization method such as ultrasound, magnetic resonance or direct visual contact is needed to ensure the correct location of the stent in the body cavity during or after the insertion. It is a purpose of the present invention to overcome this deficiency of the prior art.
It is an object of the present invention to provide a device for inserting a stent in a body cavity, such as the prostate via the urethra. The device may comprise an outer elongate tubular mantle having first and second ends, and an elongate member placed inside the mantle, having first and second end portions protruding form the respective ends of the mantle. Further, the device may comprise means for preventing said stent from sliding off of the member, and means for locating an obstacle in the body cavity.
Broadly, the device of the present invention is used as an applicator for inserting a stent into a body cavity, especially a urethral stent into the prostatic area. The stent can be made of biodegradable or bioresorbable material or biostable materials, such as stainless steel or plastic. Stents suitable for use with the invention can be in the form of, e.g., a single or multiple helical coil, or knitted tubular mesh or solid tube with holes or cuts around the tube wall. In a preferred embodiment of the present invention, the insertion device includes means for preventing the stent from sliding off of the insertion device, means for inserting the stent into, e.g., the prostatic urethra, and means for stopping the insertion of the stent and the device at, e.g., the sphincter, whereby the distal end of the stent is left in the bulbous urethra.
The stent may be released from the device in the selected location in the urethra and is left there, relieving the prostatic hyperplasia.
The device of the present invention solves problems present in insertion devices of the prior art, such as that of the ""374 patent, which requires ultrasound analysis (suprapubic or transrectal) during the insertion of the stent to localize the stent. Such localization techniques are not exact because, e.g., if the patient could not void or was incontinent after stent insertion, then cystoscopy is necessary to ensure the exact location of the stent. However, in the present invention, a balloon or cut strips (see below) divide the insertion catheter, making stent localization possible without the risk of additional cystoscopy.